#include<stdio.h>

int getScore(char g);
int main(void)
{
	int sum=0,count=0;
	float aver_score;
	char ch_level;
	
	while((ch_level=getchar())!='\n')
	{
		sum+=getScore(ch_level);
		count++;
	}
	aver_score=1.0*sum/count;
	
	printf("%.1f",aver_score);
	
	return 0;
}
int getScore(char g)
{
	switch(g)
		{
			case 'A':
				return 95;
			case 'B':
				return 85;
			case 'C':
				return 75;
			case 'D':
				return 65;
			case 'E':
				return 40;
			default:
				return -1;
		}
}
